Firefighter Basics: Low-Air Alarms

What’s the purpose of the low-air alarm on our SCBA?

In the world of firefighting, we are becoming numb to many of the alarms and devices that we are equipped with on our personal protective equipment (PPE). This numbing effect causes us to become desensitized to the alarms, vibrations, chirps, whistles, and so on. The self-contained breathing apparatus (SCBA) is one piece of PPE that has many alarms on it to help warn us of impending danger, elevated temperatures, and lack of physical movement. The one common alarm that we have on every SCBA is the low-air alarm.

So, what is the purpose of a low-air alarm on our SCBA? Is it the alarm that tells us when it is time to get out? Or is it the alarm to tell us how much air we have left? These two questions can serve as training lesson for any department as it will spur a great debate and hopefully highlight what the correct answer is.

The low-air alarm was designed and installed to inform the user of how much air he or she has left in the cylinder. It is not an alarm to tell you when it is time to get out, because you are supposed to be out of the building or on your way out when the low-air alarm sounds.


Too many firefighters are relying upon the low-air alarm to tell them when it is time to leave the building—and for the most part, they are leaving the building well after the low-air alarm has gone off. The low-air alarm is designed to be an audible, and, with some SCBA, a tactile alarm that signals to the other firefighters that someone is running out of air. It is also primarily sounding/vibrating to tell the user: YOU ARE GETTING LOW ON AIR!

low air alarms on SCBA

The evidence of low-air alarms not used for their intended purpose is the high rate of firefighters getting caught/trapped in buildings, running out of air, and then succumbing to a serious injury or worse, death. In light of this, National Fire Protection Association (NFPA) standards for SCBA changed the requirements for the low-air alarm to go off at 25 percent up to 33 percent. (See photo 1.) This increase in the end-of-service alarm has prompted many fire departments to increase their air cylinder capacities—one-hour cylinders were becoming the trend to combat the low-air problem and to give firefighters as much air as possible to do their job. It also meant that the 2216 SCBA system was going to become insufficient in terms of providing enough air capacity for the end user.

Another NFPA standard change was the integration of the heads-up display (HUD) in the face piece of the firefighter. This added component allows users to see their air consumption status at all times. Every SCBA manufacturer incorporated this extra safety feature into the face piece somehow with a series of lights; green meaning 50 percent and more of air (photo 2), yellow indicating 50 percent air left (photo 3) and flashing red indicating less than 33 percent of air remaining (photo 4).

One particular SCBA manufacturer also added proximity lights on the back of the SCBA as well as on the front of the chest gauge so that all firefighters around can see exactly what the air status is for that particular user. When the air in the cylinder starts to deplete, the lights that are displayed on the HUD are also displayed on the SCBA for a complete 360 situational awareness factor: green, yellow, and red.  

In basic training, we instruct our new firefighters to monitor their air consumption when they are wearing an SCBA by periodically checking their air gauge. This periodic check is a part of being situationally aware, which leads to knowing how much air you are using and how much you have left. Unfortunately, there has been a departure from this training as time marches on for the firefighter—the periodic check starts to drop off, and the end result is the low-air alarm going off while still inside the building.

The intended purpose of the low-air alarm is to provide firefighters with enough air so that if they were to find themselves in a situation where they must get out of the building, they will have enough air to get them out and if they get into trouble, still have some air left to bide some time for the rapid intervention team rescue.

The school of thinking in this arena needs to be changed and enforced so that the culture of the fire department is progressing for the better. This starts at the top with enforcement.

The change in culture also can take place from the bottom up—as Captain Michael Langford always says, “water boils from the bottom up.” The firefighter can have an impact on changing the culture by practicing air consumption checks all the time when using SCBA. By doing this, others will see and hopefully follow suit.

There was a time when air consumption testing took place to show each firefighter how much air they were using in a set amount of time of 30 minutes, 45, and/or 60 minutes. This was dictated by the type of cylinder each department was using. This drill gave valuable information to firefighters so that they would have a mental and physical feel for how much air they use before their low-air alarm goes off. Perhaps this testing and training should be returned to on a regular basis to help build and reinforce muscle memory. With all the changes instituted by NFPA and the technology incorporated into the SCBA, there is no excuse for any firefighter to leave the building with his or her low-air alarm going off.

Mark van der Feyst has been in the fire service since 1999 and is a firefighter with the Fort Gratiot (MI) Fire Department. He is an international instructor teaching in Canada, the United States, and India, and at FDIC. He is also the lead author of Residential Fire Rescue (Fire Engineering Books & Video). He can be contacted at


No posts to display